CONCORD, N.H. (AP) — A round, red-brick relic of this country's industrial transformation sits shakily at the southern entrance to New Hampshire's capital city, the cupola atop its conical, tree-damaged roof slumping northward. Built in 1888, the Concord gasholder building is believed to be the last of its clan in the United States with its interior works intact, a monument to a turning point in how people lived and worked: By forcing coal gas through pipes to homes and businesses, the gas works meant people were no longer captive to candles or oil lamps. After the roof was damaged during a storm in 2013, the building was temporarily repaired and now historians and preservation experts worry that without permanent repairs — and soon — the building is doomed to the rubble pile. Demolition looks to be three or four times cheaper than repairing it, but the preliminary cost estimates don't address cleaning up coal tar contamination beneath the building, company spokesman John Shore said.